The invention relates to a low-pressure discharge lamp comprising
a tubular lamp vessel which is sealed at each of its two ends in a vacuum-tight manner on current supply conductors extending to an adjacent electrode arranged in the lamp vessel;
a respective lamp cap connected to the ends of the lamp vessel, this lamp cap having contact pins connected to a respective current supply conductor.
Such low-pressure discharge lamps are well known and are used, for example, as low-pressure mercury vapour discharge lamps having a coating of fluorescent powder on the inner side of the discharge vessel.
At the starting stage of such lamps, the electrodes are heated by current passage. A potential difference then exists between the contact pins of each of the two lamp caps. The use of these lamps in a space which may contain explosive gases is therefore dangerous.
In order to avoid the risk of explosion, low-pressure discharge lamps are used in which the lamp cap has only one centrally arranged contact pin. These lamps ignite with the use of a high-frequency energy source without the electrodes being preheated.
A disadvantage of low-pressure lamps having lamp caps provided with one central contact pin is that with mechanized production the mounting of these lamp caps requires special machines, which deviate from the machines used for mounting the lamp caps having two contact pins.